Vapor electric lamp.



PATBNTED JULY 18, 1905,

R. KUGH. VAPOR ELECTRIC LAMP.

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UNITED STATES Patented July 18, 1905.

PATENT OEEIcE.

RICHARD KIIGH, OF HANAU, GERMANY, ASSIGNOR TO THE FIRM OF W. C. HERAEUS, OF HANAU, GERMANY.

VAPOR ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 794,868, dated July 18, 1905.

Application filed November 1'7, 1904. Serial No. 233,216.

To all whom, it may concern:

Be it known that I, RICHARD KUcH, a subject of the German Emperor, and a resident of Hanan, Germany, have invented certain new and useful Improvements in Vapor Electric Lamps, of which the following is a specification.

The researches made by Hewitt have shown that the characteristic curve of a gas or vapor electric lamp with mercury electrodes depends upon the specific weight of the vapor prevailing in the lamp vapor part, through which the current is passed. (Vida, for instance, the article by von Recklinghausen in the German periodical Ocnzfmlblatt for Electrotcclm'z'k, 1902, No. 23.) Therefore for various specific Weights of the vapor the strengths and the pressures of the current in the lamp will also be different. In endeavoring to procure for his lamp such a characteristic curve, by which the most favorable yield of light is obtained, Hewitt was led to make various arrangements for attaining a certain low specific weight of the vapor and preserving the same by cooling the lamp-vapor part. In

general he provided the lamp-tubes with enlargements or condensing-chambers, through which the current does not pass, which enlargements or chambers are therefore not heated, so that the vaporized mercury condenses on the walls of these enlargements or chambers, whereby the specific weight of the vapor is reduced. All the various patents of Hewitt show that the regulation of the specific weight of the vapor in the lamp-vapor part is actually eflected by proportioning the vapor-space, as 1s proved more particularly by the German patent specification No. 140,364.

In the German patent specification No.

153,687 it has already been shown that the specific weight of the vapor may be regulated in a simple manner by cooling the mercury electrodes of the lamp from without. Further experiments made since have disclosed the fact that it is chiefly the temperature of the mercury electrodes which controls the specific weight of the vapor, and this to a greater extent than .the temperature of the lamp-vapor part. This has been proved more particularly by the experiments carried on with lamps made of quartz-glass, which material permits to give the luminous lamp part a temperature of several hundred degrees centigrade by contracting the cross-section of the lamp-vapor part through which the current passes, while the mercury electrodes are cooled down to a low temperature. The theoretical explanation of this fact lies therein, that the specific weight of the vapor will necessarily depend upon the quantity of the vapor developed from the electrodes. This vaporization in turn will have to depend upon the current warmth produced at the electrodes and the loss of heat of the electrodes to without by cooling. In the said German patent specification No. 153,687 ameans was named for increasing the diversion of the heat from the electrodes. My theoretical considerations and experiments have shown that the quantity of the heat given off to without by the electrodes iswidely influenced by the size and shape of the vessels containing the electrodes and if needful in combination with cooling liquids adapted to cool the surfaces of the electrodes from without. The warmth developed at the electrodes by the are essentially depends upon the strength of the current, and the vaporization takes place only on the level of the mercury. Thus the quantity of the vapor developed at one mercury electrode depends not only upon the strength of the current, but also upon the amount of the heat given off to without from the level of the mercury within a certain time. For the same strength of the current a large top surface of the mercury will develop less vapor than a small top surface, since'the vessel-walls bounding the large top surface are of course capable of giving off more heat to without than the vessel-walls bounding the small top surface. Now that, as indicated above and is Well known, the characteristic curve of a lamp depends upon the specific weight of the vapor in the lamp-vapor part we are enabled to design lamps with exactly the same vapor-space for various pressures and strengths of the current. When assuming cessitate electrode vessels with a smaller top surface of the mercury, while, on the contrary,a higher pressure and a smaller strength of the current will require electrode vessels with a larger top surface of the mercury.

- This is of special importance for lamps made of quartz-glass, since this material is so expensive that it is necessary to utilize as much energy as possible in as small lamps as possible. Not only the size of the mercury top surfaces, but also the shape of the electrode vessels will have an influence upon the characteristic curve of the gas or vapor electric lamp. For instance, when the shapes of the vessels for electrodes are so chosen that the electric arc will strike only a part of the mercury top surfaces the arc will necessarily heat only these parts up to a higher temperature than the remaining parts, so that a circulation of the mercury will be produced by the difference in the temperatures. This circulation will also involve the lower parts of the mercury, whereby the cooling effect will be increased. For obtaining the desired characteristic curves the gas or vapor electric lamps are according to my invertion so proportioned that the vessels for the electrodes are cooled in the desired degree.

I will now proceed to illustrate the invention by the accompanying drawings.

Figure 1 is an elevation, partly broken away, of a lamp embodying the present invention. Fig. 2 is a similar view of a modified structure. Fig. 3 is an elevation of another modification. Fig. 4: is a View in elevation of another modification. Fig. 5 shows the construction of a portion of a lamp in which the electrode is cooled by a surrounding liquid; and Fig. 6 is a view similar to Fig. 5, showing amodified construction in which the electrode is surrounded by a cooling liquid.

Fig. 1 shows a lamp with a narrow and long illuminating-tube a of five or six millimeters internal diameter and from five hundred to seven hundred and fifty millimeters length. The two vessels 6 and c for containing the electrodes are much larger in diameter than the tube a, and the upper vessel 0 is so shaped that the electric arc will strike only a small part'(on the left) of the mercury top surface.

Within the mercury electrodes are located the circuit-terminals 7c and Kc. The mercury will be put into a quick circulation and be strongly cooled from without by the ambient air. This lamp is suitable for a current of four or five amperes strength and one hundred and ten volts pressure.

Fig. 2 shows a lamp with an illuminatingtube a of exactly the same size as in the preceding lamp, but with two smaller vessels Z2 and c for the mercury, the diameter of the latter being equal to that of the tube a. In opposition to the preceding lamp this lamp is arranged for a current of one to two amperes strength and several hundreds of volts pressure.

Fig. 3 shows a lamp with a wide and short illuminating-tube d of from ten to fifteen millimeters diameter and one hundred millimeters length, while the two vessels 6 andf for containing the mercury are smaller in diameterviz., only six millimeters. This lamp can be worked with a current of about five or six amperes strength and from twenty to thirty volts pressure.

Fig. 4 shows a lamp with an illuminatingtube cl of exactly the same size as before, while the two mercury vessels 0' and f are larger in diameter than before. This lamp is suitable for a current of about two amperes strength and about one hundred and ten Volts pressure.

Thus for narrow and long and for wide and short illuminating-tubes the characteristic curves of the lamps can be altered by merely proportioning the electrode vessels.

The cooling of the lamp obtained by the proper shape and size of the mercury vessels may of course be further intensified with the aid of cooling means surrounding the electrode vessels. In the German patent specification No. 153,687, already referred to above, the arrangement of metallic mantles and plates with large surfaces is described. In some cases it may be convenient to effect the external cooling ofthe electrode vessels by means of a surrounding liquid. Two examples of this kind are illustrated in Figs. 5 and 6. In Fig. 5 the vessel 9, containing mecury, is surrounded by an external vessel it, fused to it and also containing mercury. veloped by the current on the top surface of the mercury is transmitted to the mercury in the external vessel It, and the latter mercury is put into circulation by the difference of the temperatures at the inside and outside walls and by the greater external surface in contact with the ambient air, so that the cooling effect of this arrangement is considerably increased. In Fig. 6 theinternal vessel g is open at the bottom, so that it communicates with the annular space within the external vessel it. During the working of the lamp the vapor developed in the vapor-tube 7," will force the level in the internal vessel 9 downward and that within the external vessel in upward, as is shown, so that the walls of the vessel g above the level of the mercury will be cooled much in the same manner as in the lamp according to F ig..5.

The heat de- Various means for cooling the electrodes may be employed without departing from the spirit of the invention.

Having now described my invention, I declare that what I claim as my invention, and desire to secure by Letters Patent, is-

In a gas or vapor electric lamp, the combination with two electrode vessels containing mercury, of an illuminating-tube connecting said two electrode vessels, and means for passing an electric current through the whole, said two electrode vessels being so proportioned With reference to the size and crosssection of said illuminating-tube as to preserve the mercury at a desired low temperature and in accordance with the given characteristic curve of the lamp.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

RICHARD KU CH.

Witnesses:

FRANZ HASSLAGHER, ERWIN DIPPEL. 

